Screw pump



Oct. 5, 1937 F. BURGHAUSER scmaw PUMP 4 Filed Feb. 18, 1936 PatentedOct. 5, 1937 PATENT OFFICE SCREW PUMP Franz Burghauser, Nuremberg,Germany Application February 18, 1936, Serial No. 64,563 In GermanyFebruary 26, 1935 s claims. v(ci. 14n- 128) Screw pumps or axial pumpshaving one screw with one or several threads on the main spindlecooperating with one or more secondary shafts have the disadvantage,that mutual axial thrust occurs if the flanks or faces of the threadsare used for transmitting power from the main spindle to the secondaryspindles.

This sc -called drive thrust .hitherto has been absorbed by axial.bearings or by the thrust of the delivered liquid on compensating orequalizing faces. As, however, the drive thrust is not proportional tothe pressure ofthe delivered liquid a precise compensation of the drivethrust by the liquid thrust is not possible.

1'5 Constructions are also known according to which the drive thrust iscompensated by mounting on the spindles a pair of gear wheels havinginclined teeth the inclination of which is opposite to the screw thread.These gear wheels,

however, cause noises, require a considerable total length and must bemade on special machines. Moreover, the spindle bearings arrangedadjacent the gear wheels are subjected to considerably. higher stressesthan are the bearings farlranged adjacent the thread.

All the draw-backs mentioned above are, according to the invention,obviated by the fact, that collars or rings are mounted upon thespindies the conical surfaces of which roll upon each other and absorbthe drive thrust.

In the accompanying drawing one modification of the invention is shownby way of example.

In the drawing: Fig. 1 shows a longitudinal section through a screw pumpor axial pump according to the invention equipped with three spindlesand Fig. 2 is a cross section through the pump taken on the line '2-2 ofFig. 1.

Fig. 3 is a fragmentary detail section on the 40,-line 3-3 of Fig. 1.

The main spindle a drives, by means of the faces of the threads, thetwosecondary spindles b-and c. The spindles are guided in bearings and aresurrounded by a casing d.

i 4.5 On rotation of the main spindle a in the direction ofthe arrow Xshown`in Fig. 1, the drive thrust A occurs in the main spindle and drivethrusts B Vand Cof equal value occur in the two secondary spindles.According tothe invention these drive thrusts -are absorbed by thecollars or rings e, f and g the conical surfaces of which'v roll uponeach other. The drive thrust between the spindles is, therefora,absorbed by the spindles themselves and does not appear outwardly.

The use of collars or rings instead of gear wheels of the collars orrings e, f and g of the drive 10 thrust acting upon them by means of theliquid thrust acting upon the spindles. If h is the delivery chamber ofthe pump, the annular face L thereof may, according to the diameter m ofthe upper bearing pin, be so dimensioned, that a 15 liquid thrust actsupon the spindle b in a downward direction which completely orvpartially compensates the upwardly directed thrustv action.

The end surface lc of the. upper bearing pin b 20 causes no liquidthrust, because this face is connected to the suction Vchamber s by wayof bore I. The same is true of the upper surface of the bearing -pln c.In fact, both the pins b and c terminate in an annular chamber 8 whichsur- 25 rounds the shaft a. Therefore, the difference between the drivethrust and the liquid thrust only acts upon -the collars or rings e, fand g. The total liquid thrust upon the surfacesA i, t and u iscompensated by a relief piston n fixed to the 30 lspindle a.' Pressureis caused to act upon the lowerA face of this piston by way of a. boreo. The said liquid entering from the bore o then returns withoutpressure around the periphery o'f the relief piston n by way of notchesor grooves 35 f1' in the lower bearings, into the suction space s andklubricates these bearings. l

What I claim is: 1. In ascrew pump, a casing having a central bearing ateach end and having a plurality of 40 other bearings at each endequidistantly spaced from each other and equidistant from the centralbearings, a central screw impeller having journals mounted in theAcentral bearings, other screw impellers having journals mounted in the-re- 45 being provided respectively with inlet an Jsttftiet ports, abevel grooved friction gear on t trai impeller, and a friction gear oneach of the remaining impellers and having a bevelled face 55 fitting inthe groove oi' the first mentioned friction gear.

2.` In a screw pump, a casing having a central bearing at each end andhaving a plurality of other bearings at each end equidistantly spacedfrom each other and equidistant from the centrai bearings, a centralscrew impeller having journals vmounted in the central bearings, otherscrew impellers having journals mounted in the remaining bearings, saidcentral screw impeller being of opposite hand to and meshing with theremaining screw impellers, a housing fitting around said screw impellersand supported by the casing to divide thel space therein into suctionand expulsion chambers, said chambers being provided respectively withinlet and outlet ports, said casing being provided at the suction endwith a pressure cylinderA into which the bearings at said suction endopen, one of the Journals of the central impeller extending into saidcylinder, a piston xed on said last journal in said cylinder, saidcentral impeller being provided with a duct extending from the expulsionchamber and opening through the end of the last mentioned journal, abevel grooved friction gear on the central impeller, and a friction gearon each of the remaining impellers and having a bevelled face fitting inthe groove of the first mentioned friction gear.

3. In a screw pump, a casing having a central bearing at each end andhaving a plurality of other bearings at each end equidistantly spacedfrom each other and equidistant from the central bearings, a centralscrew impeller having journals mounted in t e central bearings, otherscrew impellers having ournals mounted in theremaining bearings," saidcentral screw impeller being of opposite hand to and'meshing with theremaining screw impellers, a housing fitting around said screw impellersand supported by the casing to divide the space therein into suction andexpulsion chambers, said chambers being provided respectively with inletand outlet ports, said casing being provided at the suction end with apressure cylinder into which the bearings at said suction end open, oneof the journals of the central impeller extending into said cylinder,

a pisto'n xed on said last journal in said cylinder, said centralimpeller being provided with a duct extending from the expulsion chamberand opening through the end of the last mentioned journal, saidremaining impellers being each provided with a duct leading from thesuction chamber and opening through the end of the journal of theimpeller at the expulsion end of the casing, a pressure chamber formedin the journals for said last named impellers at the expulsion end ofsaid casing, said last named ducts opening into said last namedchamber', a bevel grooved friction gear on the central impeller, and afriction gear on each of the remaining impellers and having a bevelledface fitting in the groove of the first mentioned friction gear. FRANZBURGHAUSER.

